• Weed & Turfgrass Science
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• v.6 no.4
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• pp.333-344
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• 2017

This study was conducted to examine the effect of cool-season grass overseeding on the green period, turf quality and density in zoysiagrass lawn. Treatments were perennial ryegrass (PR) overseeding ($60g\;m^{-2}$) on medium-leaf type zoysiagrass, Kentucky bluegrass (KB) overseeding ($20g\;m^{-2}$) on medium-leaf type zoysiagrass and narrow-leaf type zoysiagrass, and no overseeding on medium-leaf type zoysiagrass. Overseeding of KB or PR effectively provided quality improvement of zoysiagrass lawn by extending green-period about one month in spring and two months in fall season. PR overseeding showed quick green cover within 2-3 weeks but decreased the quality of overseeded zoysiagrass lawn during the summer season. Whereas, KB overseeding showed slow green cover taking two to three month after seeding but provided stable and good turf quality throughout the years. KB or PR overseeding significantly increased the turf density of zoysiagrass lawn except the period of summer depression of PR. The ground coverage of cool-season grasses ranged from 30 to 80% with considerable seasonal variation. As a result, KB and PR have their strengths and weaknesses as an overseeding material. Thus, the use of KB and PR as a mixture would provide better overseeding performance in zoysiagrass lawn.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.403-415
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• 2021

Seasonal development of Parthenolecanium corni was observed from 4 Jun. 2019 (nymph) - 25 Jun. 2020 (1^st Gen. nymph) in blueberry shrub in Sacheon city, Gyeongsangnam-do. To investigate their development, more than 5 twigs sprouted in 2018 were taken from the farm nearly weekly basis. The development of each scale were examined under the stereomicroscope and chemical control was conducted in the blueberry shrub with available three insecticides. The results on the development period and Centigrade Degree-Days accumulation (DDC) obtained are as follows: egg-laying period (peak): 12 -26 May 2020 (24 May)(DDC, 110.0-188.5 (173.6)); egg-hatching period (peak): 9 - 23 June 2020 (19 June)(DDC, 325.2-480.8(435.6); egg period: 26 days; nymph movement from overwintered adult to new leaves 16-25 June 2020 (DDC, 410,5-500.4); nymph movement from leaf to twig (peak) to become adult: 4-18 Feb. 2020 (8 Feb.). Eggs no. /adult (range): 956.8 ± 73.4 (13 - 3497). Size (mm) of egg, 0.29 ± 0.020(L), 0.15 ± 0.013(W); of egg-hatched nymph, 0.35 ± 0.018(L), 0.18 ± 0.007(W), 0.09 ± 0.007(eye distance); and of adult, 4.30 ± 0.893(L), 2.64 ± 0.520(W). The egg-hatched nymphs from the overwintered adult moved to the backside leaf of new shoot in which they found about 95% until leaf is falling by early February in next year. They overwintered as 2^nd instar and occurred univoltine. For the control of the 1^st instar crawler, three insecticides treated on 16 and 30 July at the registered dose for Ceroplastes japonicus. Acetamiprid 8WP showed 96.9% mortality at 21 days after 1^st treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.68 no.4
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• pp.438-444
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• 2023

Italian ryegrass (Lolium multiflorum Lam.; IRG) sowing season is delayed due to the autumn rainy season. Therefore, to address this problem, transplanting date and plant density were investigated. Transplant times investigated were October 20th, October 30th, and November 10th and planting densities were 50, 70, and 80 hills per 3.3 m². The plant height, leaf area index, and plant coverage rate were high in the following order: October 20th, October 30th, and November 10th. There was no significant difference among planting densities. In addition, the number of tillers and dry weight before and after wintering were high on October 20th. In terms of yield components, the number of tillers, dry weight, and seed yield per unit area were higher with the transplanting date of October 20th than with transplanting on November 10th. There was no difference in seed yield between the planting densities of 80 and 70 hills per 3.3 m². However, seed yield was low at 50 hills per 3.3 m². In conclusion, the transplanting time for stable seed production is late October, and optimal plant density is 70 and 80 hills per 3.3 m². A stable interplanting number before wintering will contribute to the seed yield.

• Korean journal of applied entomology
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• v.56 no.2
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• pp.213-222
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• 2017

Among flies inside mushroom growing rooms in three farms, Lycoriella ingenua and Megaselia tamilnaduensis were the most common and dominant species during Pleurotus ostreatus cultivation in Korea. In the past, generally, during the incubation period, a low density of mushroom flies was observed in all farms. After the first harvest, mushroom flies density tended to increase sharply. However, many mushroom flies were observed in the summer, despite that season corresponds to the incubation period. This is because annual cultivation systems provide a safe overwintering place compared to seasonal selective ones. The ecology of mushroom flies varies greatly according to the cultivation system. We confirmed that a fallow period reduced the density of mushroom flies. From a survey of the three dimensional distribution of mushroom flies in a growing room, we observed that M. tamilnaduensis showed more positive phototaxis and a higher variation per point of capture than that by L. ingenua. Through this study, two mushroom fly species were identified in the survey farms, with markedly different three dimensional distribution patterns.

• Korean Journal of Ichthyology
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• v.5 no.2
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• pp.184-193
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• 1993

The distribution, and length and age compositions of Johnius belengeri were studied using samples collected by an otter trawl from the five different coastal waters of Korea ; Asan Bay, Cheonsu Bay, waters off Yeongkwang and Samchonpo, and Yeongil Bay. This fish showed a high density of 1,147 individuals/$10,000m^2$ and predominated in abundance of the demersal fish in the coastal water off Yeongkwang. The mean density was 94 individuals/$10,000m^2$ in Cheonsu Bay and 8-24 individuals/$10,000m^2$ in Asan Bay and in the water off Samchonpo. Few fish were collected from Yeongil Bay. J. belengeri occurred from spring to autumn in the study area and showed a relatively high density in spring or in summer. The fish collected in spring and in summer composed of adults of age group I, II and III. Some juveniles began to occurred in the waters off Yeongkwang and Samchonpo from summer. The fish collected in autumn consisted mainly of the fish of age group 0. It implies that the adults after spawning moved out from the embayments for feeding. but the young fish stayed and grew in the embayments until late autumn when they migrated to the offshore water for wintering.

• Korean Journal of Ecology and Environment
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• v.38 no.3 s.113
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• pp.352-360
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• 2005

Acheilognathus signifer is distributed widely in high density in the Naechon-stream. The order of this-stream was 2 ${\sim}$ 4 and the water width is wide but the depth is relatively shallow and the sinuosity is 1.83, which indicates a meandering stream. The water width/stream width ratio is 1.59, which suggests moderate entrenchment. Naechon-stream was classed as B type by Rosgen (1995). The natural habitat of A. signifer is a slow flow velocity pool, like a backwater pool, which is made up of piled up boulders that restricts the flow of water. The stream bed is made up of boulders and sands that enable the spawning host to inhabit. A. signifer selects a microhabitat where the boulders furnish hiding places. The Habitat of A. signifer is strongly affected by the existence or not there of U. douglasiae sinuolatus. After hatching from the mussel, A. signifer inhabits the surface of the water. It then moves to the low layer once it acquires swimming ability. While A. signifer inhabits the river in summer, A. signifer moves to the deeper layers in winter, where there are the refuge like rocks and boulders. In spring A. signifer moves from the deep water to the river line where the mussels reside.

• Asian Journal of Turfgrass Science
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• v.19 no.2
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• pp.131-140
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• 2005

This study was conducted to compare cold tolerances and growth rates of 5 basic species, commercial lines, and breeding lines of zoysiagrass. Total 41 zoysiagrasses were tested at the northern part (Jeokseong-myeon) and the middle part (Cheonan) of South Korea. Cold tolerance (survival rate during winter), growth rate, green-up speed, and density data were collected visually. Four types of zoysiagrasses (Z. matrella, Z. tenuifolia, USm, and S4M2) with genetic characteristics of Z. matrella died during winter cold, while the others survived. Midium leaf type zoysiagrasses, such as Anyang1, Samdeock1, Anyang2, SJ21, and Pyeongdong, with genetic characteristics of both Z. sinica and Z. macrostachya showed vigorous growth rate one year after planting at the northern part (Jeokseong-myeon). Twenty nine ($70.7\%$) zoysiagrasses showed vigorous growth rate, but the other twelve ($29.3\%$) zoysiagrasses died by cold and drought condition at the middle (Cheonan) part of S. Korea. Anyang2, AJ9-7, Samdeock1, Samdeock2, Samdeock3, and Zenith-C showed vigorous growth rate even though cold and drought environmental condition were artificially provided at these region. But, SJ2-19, NSm, 88Mey, 88Mey-7S, 88Mey-9S, SJ2l-10, ASm, and DBm which did not die at the northern part, showed serious injury at the middle part of S. korea. From this results, we can conclude that drought is as important factor as low temperature for zoysiagrasses during winter.

• Korean journal of applied entomology
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• v.48 no.4
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• pp.423-429
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• 2009

Characteristics of habitat alteration and post-embryonic development of Paratlanticus ussuriensis were investigated in the mountain region of Bitanri, Yeongdong county, Chungcheongbuk-do from 2007 to 2009. Overwintered eggs under the ground in the hillside were hatched from late March to early April. The soil temperature during this season was $7{\sim}14^{\circ}C$. Young nymphs lived mainly at the hillside by eating oak tree leaves but the 3rd or 4th instars switched their habitat to orchards near the hillside in early May, which is the time for sprouting of peach leaves. Old nymphs developed into the adult stage at the orchards in late May and moved back to the hillside in late June. Duration of post-embryonic development from the first instar nymph to adult was 49.2 days after 7 moltings at $25^{\circ}C$. Female adults collected from the field had long ovipositor (26.2 mm) and were slightly longer in the body length, hind femur, tegmen and pronotum than those of males.

• Proceedings of the KOR-KST Conference
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• 1998.10b
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• pp.508-508
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• 1998

위험물 차량사고는 일반차량의 교통사고시 발생하는 인명피해, 재산피해, 교통지체 외에 부가적으로 환경적 영향에 의한 엄청난 인명 및 재산손실을 유발시킬 수 있다. 따라서 이러한 위험물차량사고를 예방하고 피해를 최소로 줄이기 위해서는 위험물수송경로의 신중하고 체계적인 결정이 필수적이라 할 수 있다. 외국의 경우, 위험물의 방출이 미치는 환경적 영향에 대한 인식이 확대되면서 위험물 수송시 응급처리에 관한 연구, 위험물 수송에 따른 위험도 평가에 관한 연구, 위험물 수송시 고려해야할 여러 조건에 관한 연구, 위험물 수송경로 설정에 관한 연구 등이 진행되고 있다. 반면에 우리 나라는 위험물차량관리와 사고처리에 대해 실시간적인 관리를 목표로 하는 국가차원의 계획을 수립하고는 있지만, 현재 이와 관련된 연구는 거의 없는 실정이다. 앞으로 산업발달에 따른 위험물수송량의 증가와 환경의식의 변화에 따라 위험물수송 및 사고처리 등에 관한 연구가 필요할 것이다. 따라서, 본 연구는 위험물차량의 운송경로를 결정할 때 고려해야 할 여러 가지의 기준 및 목표에 따라 위험물수송경로를 설정하는 모형을 제시함으로써 위험물수송에 수반되는 위험을 최소화하면서 위험물차량의 통행시간, 거리, 비용 등을 최적화하여 위험물수송의 안전 및 운영효율성을 향상시키고자 한다. 먼저, 위험물 수송경로의 기준지표로 사용될 위험도를 산정하기 위해 링크 주변노출인구, 밀도 등을 변수로 하는 모형식을 제안하고, 두 번째로 산정된 위험도를 기반으로 최적경로를 결정하는 알고리즘을 제안하였다. 마지막으로 가상 네트웍에 본 연구에서 제안된 모형을 적용하고 현재 일반적으로 사용되는 최단경로와 비교·분석하였다.것은 운송거리와 운송비용이 각각 주요한 변수라는 것이다. 모형의 타당성을 검증하기 위해서는 logilikelihood 값을 구하여 $\rho$^2분석을 시행하였다. 여기서는 각 품목별로 $\rho$^2값이 약 0.15~0.3의 비교적 높은 수치를 보여주고 있으므로 모형의 설명력이 어느 정도 있다는 것이 아울러 증명이 되었다. 상관관계에 대한 분석에서는 영업용 차량간의 상관관계가 높게 나타났으며, 이는 곧 영업용 화물차량을 적재중량별로 구분하는 것이 별 의미가 없음을 의미한다. 다시 말하면 자가용 차량을 보유하고 있지 않은 회사는 다른 운송전문업체에 화물운송을 의뢰하게 되므로 출하중량에 따라 화물차량을 구분하는 것에 대해서 그다지 큰 고려를 하지 않는 것으로 해석할 수가 있다.적합함을 재확인함. 6. 혼잡초기를 제외한 혼잡기간 중 대기행렬길이는 밀도데이터 없이도 혼잡 상류부의 도착교통량과 병목지점 본선통과교통량만을 이용하여 추정이 가능함. 7. 이상에 연구한 결과를 토대로, 고속도로 대기행렬길이를 산정할 수 있는 기초적인 도형을 제시함.벌레를 대상으로 처리한 Phenthoate EC가 96.38%의 방제가로 약효가 가장 우수하였고 3월중순 및 4월중순 월동후 암컷을 대상으로 처리한 Machine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압

• Parasites, Hosts and Diseases
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• v.33 no.1
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• pp.19-26
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• 1995

Ecological studies of Aedes togoi, the vector of malayan filariasis, were ci,wind out at Tolsando, Yosu and Sokcho area in 1991. The adult population of Aedes togoi was continuously appeared from the first week of April to the end of November showing the highest density in .truly. The larvae of Aedes togoi were found at rock pools from March to December in Sokcho area and the density was highest in July and August, whereas in the southern coastal area (Yosu), the larvae were found throughout the year and the density was the highest in Tune. The rate of larvae inhabited below 0.5% salinity was 45.7% in Sokcho and 51.7% in Yosu. The feeding activity of Aedes togoi was nocturnal, with the peak period of 01 :00-03:00 hours. Indoor feeding activities were slightly higher than outdoors showing the biting ratio of 1 :0.8 (indoor: outdoor). The average number of Aedes togoi attracted to CO2 gas was 8.5 whereas 117 Anophelei sinensis was attracted. The result indicates that CO2 is not an effective attractant for host seeking of Aedes togoi compared to Anopheles sineteis. The most common place was bedroom with 54.5% of total collections and next to stock place (18.2%), floor(9.1%) and kitchen (9.1%).